1. Field of the Invention
The present invention relates to a network system, a direct-access method, a network household electrical appliance, and a program that enable the network household electrical appliance to be controlled from a controlling device through a network.
2. Description of the Related Art
Examples of a method for access from a controlling device on the Internet to an in-home controlled device include a DDNS (Dynamic Domain Name System) method and a mail method.
In the DDNS, the in-home controlled device registers its own address in a DDNS server in advance and receives designation of a domain name and a port number from the controlling device on the Internet side. The controlling device can thus access the controlled device.
As a protocol for realizing real-time communication, an XMPP (extensible Messaging and Presence Protocol) is available (see Non-patent Document 1). One of real-time communication systems using this XMPP is instant messaging (IM) (see Non-patent Document 2). In the instant messaging (IM), it is checked whether an IM client (counterpart who can make IM exchange) is online on the Internet, and when the IM client is online, chatting, file exchange, and so on with the IM client can be performed.
Also, as a protocol for invoking data or a service in another computer, a SOAP (Simple Object Access Protocol) is available (see Non-patent Document 3). In communication using the SOAP, messages in each of which incidental information called an envelope is attached to an XML (eXtensible Markup Language) document are exchanged using a protocol such as an HTTP (Hyper Text Transfer Protocol). Since both a client using a service and a server providing the service have SOAP generation/interpretation engines, an object can be invoked between different environments.
As a system for establishing a session between a server and a client terminal and delivering a content from the server to the client terminal through a network, a system capable of, when the delivery of the content is interrupted by disconnection of the session, establishing a new session and restarting the delivery is known (see Patent Document 1).
[Non-patent Document 1] “Extensible Messaging and Presence Protocol (XMPP): Core”, RFC3920, The Internet Engineering Task Force (IETF), October, 2004
[Non-patent Document 2] “Extensible Messaging and Presence Protocol (XMPP): Instant Messaging and Presence”, RFC3921, The Internet Engineering Task Force (IETF), October, 2004
[Non-patent Document 3] “SOAP Version 1.2”, W3C Recommendation, World Wide Web Consortium (W3C), June, 2003
[Patent Document 1] Japanese Patent Application Laid-Open No. 2003-050761
[Patent Document 2] Japanese Patent Application Laid-Open No. 2007-318185